PROBLEM: ENGINE FLOODS
PROBLEM 1: ENGINE IDLES ROUGH AND
STALLS
Possible Cause Corrective Action
Dirt or foreign particles
are preventing inlet
needle from seating.
Flush out inlet seat and
clean inlet needle.
Worn inlet needle. Replace.
Punctured float. Replace.
Incorrect float setting. Reset float.
Carburetor is loose. Air
leaks past mixing
chamber cover.
Tighten bolts securely.
Tighten cover or re-
place gasket.
Fuel tank air vent closed
or restricted.
Check - Air vent must be
open all-the-way and
free from restrictions.
Main nozzle or idle
nozzle air bleed holes
plugged.
Blow out with com-
pressed air.
PROBLEM: ENGINE RUNS TOO LEAN
Possible Cause Corrective Action
Fuel level too low. Reset float level.
Clogged high speed jet. Check and clean.
Restricted fuel flow to
carburetor.
Check fuel lines and fil-
ter(s) for restricted
flow.
Incorrect high speed jet. Refer to main jet chart
and replace with prop-
er jet.
Idle mixture set too lean. Adjust to run richer.
Air leakage into fuel sys-
tem.
Check fuel line connec-
tions, hose clamps,
fuel pump, and fuel
outlet tube (located in
fuel tank) for loose fit-
tings.
Anti-Siphon valve re-
stricting fuel flow.
Refer to “Checking for re-
stricted fuel flow
caused by Anti-Siphon
valves.”
PROBLEM: ENGINE RUNS TOO RICH
Possible Cause Corrective Action
Fuel level too high. Reset float to correct
level.
Carburetor floods. See preceding “Engine
Floods”
Idle nozzle air
holes plugged.
Blow out with com-
pressed air.
Restricted air flow. Check cowl air inlet and
carburetor for obstruc-
tions.
Main Fuel Jet loose. Retighten Jet.
Possible Cause Corrective Action
PROBLEM 2: ENGINE RUNS UNEVEN OR
SURGES
PROBLEM 3: ENGINE WILL NOT ACCELERATE
A pinched, cut or re-
stricted fuel line; also
loose fuel line connec-
tion.
Check all fuel lines and
replace as needed.
Check and tighten all
fuel line connections.
A dirty or restricted fuel
filter.
Check, replace, or clean
all fuel filters.
Restricted filter in fuel
tank.
Clean by rinsing in clean
lead-free gasoline or
kerosene.
Improperly mixed fuel;
contaminants (water,
dirt, etc,) in fuel.
Check fuel and replace,
if necessary.
An inlet needle (in carbu-
retor) that is either
stuck open or closed.
(A needle, that is stuck
open, will cause a
flooding condition. A
needle, that is stuck
closed, will prevent
fuel from entering car-
buretor.)
Remove and replace
with new inlet needle.
Incorrect idle mixture ad-
justment.
Re-adjust.
Damaged fuel pump dia-
phragm.
Replace.
Carburetor is loose. Tighten bolts securely.
Chamber cover leaking
air.
Tighten or replace gas-
ket.
Off idle holes plugged. Blow out with com-
pressed air.
Improper main jet or re-
stricted jet.
Clean or replace with
proper jet (refer to
“Main Jet Chart”).
Damaged reed(s). Inspect reeds as outlined
in Section 4A.
A crack in the fuel pick-
up outlet tube (located
in fuel tank).
Replace.
FUEL SYSTEMS - 3A-990-817643R1 DECEMBER 1996
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